For some years now, powder coating materials, commonly known as powder coatings, have been finding an ever larger field of use. Powder coating materials are in the form of a dry powder which is applied in finely divided form to the surface of the article to be coated, generally with the aid of electrostatic charging, and is subsequently "dried", i.e., baked. In the course of baking, which usually takes place at temperatures between 130 and 220.degree. C., crosslinking reactions and film formation turn the powder into a solid coating on the workpiece. Powder coating materials of this kind offer a range of advantages. For instance, the pulverized consistency of the coating material removes the need to operate with solvents. Accordingly, all of the environmental problems commonly associated with the evaporation of the solvents disappear with powder coating materials. Furthermore, a saving is made in terms of the heating energy otherwise necessary for the evaporation of the solvents. A further advantage of powder coating materials is that material which has not remained adhering to the workpiece can be collected on the floor of the powder booth and simply used again. In this way, a degree of powder utilization of up to 98% can be achieved. In addition to cost advantages, this increased degree of utilization also brings with it a far lesser degree of environmental burden than in the case of customary coating materials. Powder coating materials are prepared from binders, hardeners, fillers, pigments and additives. In respect of the binders and hardeners used, modern-day powder coating materials are generally based on one of the following polymer classes: epoxies; epoxy-polyester mixtures; polyesters; polyesters/isocyanates (polyurethanes); polyacrylates.